Electricity is produced by fuel cell power plants which electrochemically convert a hydrocarbon-containing fuel stream, or a hydrogen stream, and an air stream into electrons and water. A fuel cell power plant can consist of a single fuel cell stack, or multiple fuel cell stacks. The choice of power plant configurations can depend on the desired electrical power output, and/or also on the available space that the power plant can occupy.
When the utility of having a plurality of interconnected fuel cell stacks is desirable, it has been suggested that fuel cell stacks in the power plant can be connected together in tandem, so that the fuel exhausted from a first stage of the stacks in the power plant can be routed to one or more fuel cell stack(s) in a second stage of the power plant and used as a fuel supply for the stack(s) in the second stage of the power plant. A schematic illustration of such a system is disclosed in European Patent Specification No. 0 263 052 B1, published Feb. 27, 1991. This patent publication shows multi stack fuel cell power plants wherein the stacks are supplied with reactants in parallel, in FIG. 1, and also wherein the stacks are supplied with reactants in tandem in FIGS. 2 and 3. The system described in the aforesaid patent publication suggests the use of a plurality of modular building block-type units for the several stages in the power plant. This approach involves the use of a plurality of reactant transfer lines from one stage to the next, which can become complicated and require complicated reactant transfer line assemblies.
It would be desirable to be able to utilize the tandem or serial connection approach for a multi-fuel cell stack power plant with a simplified connection between the individual stacks in the first stage of the power plant, and between the first stack stage and a subsequent stack stage in the power plant and which guards against water condensation in the fuel stream which is directed from the first stack stage to the subsequent stack stage. We have devised a simplified thermally insulated single manifold structure which accomplishes the aforesaid desirable result.